JPS6044726A - Safety combustion device - Google Patents

Abstract

PURPOSE:To ensure an improved safety, by arranging such that a fuel supply to a burner is automatically interrupted in the case of burner unignited or flame extinguished during combustion, and the burner is unable to be ignited or burnt unless unburnt gas is exhausted from a device after the lapse of preset time. CONSTITUTION:By opening a hot water feed cock 9, a water flow switch 9 is turned ON and a condenser C increases its voltage higher than a reference voltage. A comparator 12 outputs an operation signal to a combustion actuation circuit 11 to effectuate an ignition trial a1. In the case of ignition failure, however, a first switch circuit 16 is turned into a high-voltage state while a second switch circuit 17 is in turn maintained in a low-voltage state. An electrical discharge is thus effectuated via a second discharge circuit 14, so that the voltage of condenser C may be reduced to zero. The charge of condenser C is started after the condenser C is fully discharged and consequently if an operator knows the ignition failure and attempts to reignite, the ignition trial a1 is effectuated after a prepurge a2 is finished, provided that the water flow switch 9 is turned ON prior to the finish of prepurge a2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention automatically ignites and burns a burner when a water flow switch is turned on when a hot water tap is opened, and when the water flow switch is turned on when the hot water tap is closed. The burner automatically extinguishes when turned off, and in addition, when the burner fails to ignite or burns out in the middle of combustion, the fuel gas supply to the burner is automatically cut off, and safety is prevented from abnormal combustion such as explosion. First, instant water heaters, etc. that are designed to prevent the burner from igniting and burning until the unburned gas inside the vessel has been exhausted after a set time has elapsed, that is, the pre-purge for the set time has not been performed. As shown in the figure, this combustion control device includes a capacitor (Q) that can be charged by turning on a power switch such as the water flow switch, and a capacitor (C1) that can be charged when the voltage of the capacitor (C1) becomes higher than the reference voltage. A combustion operating circuit (11) for ignition and combustion is provided with a comparator (12) for outputting an operating signal, and the capacitor (0) is configured to be discharged in the event of a misfire or new starter. The present invention relates to a combustion safety device in which the pre-purge time required for subsequent ignition is set to 1 or more depending on the charging time of the capacitor +01.

In such a combustion safety device, after the burner ignites, it is necessary to stop the output of the comparator and stop the ignition operation of the combustion operation circuit, and then discharge the capacitor based on the ignition of the burner. , as shown in FIG. 4, the first discharge circuit (18') discharges the capacitor tel based on the ignition of the burner, and the second discharge circuit (18') discharges the capacitor fil in the event of a misfire or a new burner.
4') Similarly, condensation? The device was configured to discharge through a resistor (R') so that the voltage at +01 becomes zero, but this method had the following drawbacks.

In other words, when the fuel gas supply to the burner is cut off and combustion is stopped due to the operation of the combustion operation circuit based on the OFF of the power switch, pre-purging is not required for subsequent ignition, but in the conventional device, Even if combustion is stopped by turning off the power switch as mentioned above, the voltage of the capacitor will be discharged to zero through the former discharge circuit mentioned above, so it will not be possible for the next ignition to occur. However, unnecessary pre-purge is performed at the set time, so the water flow switch, which is the power switch, is often turned off momentarily due to switching between the shower nozzle and the water pressure U1, which is particularly likely to occur during hot water supply. In the case of a container, the water flow switch is turned off and then turned on instantly.
However, even if the pre-purge time has elapsed, cold water is still delivered until the end of the pre-purge time, which is very inconvenient to use.

In addition, in conventional devices, the pre-purge for ignition after a misfire and a new ignition is performed after the user notices the misfire and a new ignition and turns off the power switch. Since it was configured to start from the beginning, it had the following drawbacks.

In other words, if the user notices a misfire or a new starter and turns on the power switch early, the user can re-ignite the fire after a misfire or a new starter by simply waiting a little longer than the pre-purge time. For example, in a water heater, the user notices a misfire or a new user when hot water does not come out from the boiler or the hot water changes to cold water. It takes a considerable amount of time to complete the process, so the waiting time required for misfire and ignition after a new ignition is reduced.
The user notices the misfire and the new person and turns on the power switch.
This is the sum of the time required for K and the pre-purge time, making it difficult to use.

The present invention aims to eliminate such conventional drawbacks.

The characteristic structure of the combustion safety device according to the present invention, which was taken to achieve the above object, is a power switch and an O
a capacitor that can be charged by N; a comparator that outputs an activation signal to a combustion activation circuit that ignites and burns the burner when the voltage of this capacitor becomes higher than a reference voltage; @l discharge circuit that discharges the voltage of the capacitor to a value slightly lower than the reference voltage, and a state in which the power switch is turned on after a certain period of time has passed after the power switch is turned on. a second discharge circuit that discharges the voltage of the capacitor to zero or almost zero when the burner is in the extinguished state, and the capacitor discharges through the second discharge circuit, and The present invention is configured to start charging the capacitor when a certain period of time has elapsed after the power switch was turned on, or when the burner was extinguished.

To summarize, the comparator output is stopped based on burner ignition. In order to set the pre-purge time, the capacitor voltage should be discharged to zero or almost zero! ! On the other hand, in the first discharge circuit, the voltage of the capacitor is slightly lower than the reference voltage, that is, the power switch is turned 0N (7
In this case, the structure is configured so that the electric discharge can be made to rise above the standard '1kIUf in a very short time compared to the above-mentioned pre-/(-ji time), and also to prevent misfires and new starters. Prepurge, which is required for subsequent re-ignition, is configured so that it does not turn on the power switch, but starts when there is no ignition or when IIJi becomes large.

-1-, The operation of the present invention having the above characteristic configuration is as follows.

fl+ When there is no ignition or a new ignition, the voltage of the capacitor is discharged to zero or almost zero through the second discharge circuit, so pre-purging is ensured for the set time during the ignition after the above-mentioned misfire or new ignition. can be done.

(2) During ignition and combustion, the voltage of the capacitor can be discharged to a value slightly lower than the reference voltage via the first discharge circuit, so the ignition operation ω1 of the combustion operation circuit is automatically performed based on ignition. However, if the power switch is turned off for a moment, combustion will be stopped by turning off the power switch, but the voltage of the capacitor will be set to the standard within a short time by turning the switch on shortly after the switch is turned off. By raising the voltage above that level, ignition and combustion can occur immediately.

(3) Pre-purge for a set period of time starts immediately after a misfire or catastrophe, so in the event of a misfire or a new ignition,
You can ignite it just by waiting for the pre-purge time.

Therefore, although the present invention can safely perform ignition after a misfire or a new ignition, it is particularly suitable for water heaters where the phenomenon of the water flow switch turning off momentarily frequently occurs, and where the detection of a misfire or a new ignition is often delayed. As a result, usability has been significantly improved.

Hereinafter, embodiments of the configuration of the present invention will be described based on the drawings.

Water heating heat exchanger (1), burner (2), igniter (
3), an instant water heater equipped with a flame rond (4), and a switching valve (5) is installed in the water supply channel to the #I heat exchanger 1).
) and the shower nozzle (
A water flow switch (9) is provided which is turned on when a water flow is generated by opening the hot water tap (8) in response to the hot water tap (7).

A solenoid valve (lO
) is interposed.

As shown in FIG. 2, the device for controlling the combustion of the burner (2) opens the solenoid valve (10) based on an activation signal and ignites the igniter (3) for a certain period of time. The burner (2) is actuated to ignite and burn, and the solenoid valve (l
A combustion operation circuit (11) that closes the capacitor (0) that can be charged by turning on the water flow switch (3)
When the voltage of the capacitor +01 and the resistor (R1) for setting the charging time of the content-rtc++ becomes higher than the reference voltage divided by the resistors (R,) and (R3), the combustion Made in the operating circuit (U)! A comparator (+2) that outputs the gl+ signal and the burner (2)
) is ignited and burned, the first discharge circuit haze and the water flow switch (9), which discharge the capacitor so that the voltage becomes a value slightly lower than the reference voltage, are turned on.
After a certain period of time has elapsed since the ignition trial, when the water flow switch (9) is on and the burner (2) is in the extinguished state, the voltage of the capacitor (Q is zero). The second discharge is made so that
a discharge circuit (14), and the capacitor l
ot is discharged through the second discharge circuit θ4) and a certain period of time has passed since the water flow switch (9) was turned on (that is, at the end of the ignition trial), or the burner (2) is extinguished. It is configured to start charging the capacitor (Q) when

The first discharge circuit (I terminal is the frame rond (4)
The switch circuit (15) switches to a low voltage state based on the flame detection of 15) of the capacitor fol (
(+) side and a resistor (Ra) connected to the +) side.
Furthermore, with the value of this resistor (R4), the con- ? f
The voltage of ol is set to be slightly lower than the reference voltage.

The second discharge circuit (I4) Vi, after the trial,
In other words, after the igniter (3) is activated, until the water flow switch (9) is turned off, the @l switch circuit 0 (2) and this first switch circuit (16) are in a low voltage state. When in a low voltage state, a transistor (Tr, ) turns on, and a second transistor (Tr2) turns on when this transistor (Trl) turns on.
It is connected to the (+) side of the converter +jto+ via the second transistor (Tr2) and the resistor (R4), and switches to a low voltage state based on non-detection of the flame rond (4). Accordingly, a second switch circuit (+7) for discharging is provided.

The operation will be explained based on FIG. 8. When the water flow switch (9) is turned on due to the opening operation of the hot water tap (8), the voltage of the con- 4j (0) becomes higher than the reference voltage, and the comparator ( An activation signal is output from I2) to the combustion activation circuit (U), and an ignition trial (al) is performed.

When the burner (2) ignites and burns as a result of this ignition trial (a), the switch circuit (15) is switched to a low voltage state, and the voltage is discharged through the first discharge circuit 03), and the voltage of the capacitor 01 is becomes a value slightly lower than the reference voltage, and the combustion operation circuit (U
), the output of the II7 signal to the combustion operation circuit (F) is stopped.
11) The ignition operation stops.

In the case of misfire, the first switch circuit (l[I) is switched to a high voltage state, while the second switch circuit (17) is maintained in a low voltage state, so that the second discharge circuit 04)
is discharged through the terminal so that the voltage on the con-an-r tel becomes zero. Then, since the charging of the con-an 4j (o) starts from the moment when the discharge of the con-an 4j (o) ends, the user notices the misfire and closes the hot water tap (8), and starts the hot water supply anew. When attempting to ignite by opening the tap (8), if the water flow switch (9) is turned ON before the pre-barge (a2) is completed due to the opening of the hot water tap (8), V
C. From the time the pre-purge (a2) is completed, or after the pre-purge (a2) is completed, the water flow switch (
From the point in time when 9) is 0ONI, an ignition trial c) is conducted.

When a new combustion occurs in the combustion state, KII'i, discharge occurs in the same manner as in the case of no ignition, and subsequent ignition occurs in the same manner.

In the combustion state, when the hot water tap (8) is closed, the water flow switch (
9) is turned off, the combustion operation circuit (ul) is turned off by the solenoid valve (I
ll) is operated to close, and combustion is stopped. At this time, the switch circuit (I) switches to a high voltage state and discharge from the first discharge circuit θ is stopped, and the second switch circuit (+'7) switches to a low voltage state @VC, but the first Since the switch circuit (15) is switched to a low voltage state and the second discharge circuit (I4) is maintained in a non-discharge state, the voltage of the capacitor tC1 is a value slightly lower than the reference voltage, that is, the voltage of The water flow switch (9) is turned on without placing the
, the value becomes such that the voltage can rise above the reference voltage in a very short time compared to the pre-purge time described above. Therefore, for example, due to the switching operation of the switching valve (5) or fluctuations in water pressure, the water flow switch (9) may
If it is turned OFF, turn the water flow switch (9) to OFF.
Although the combustion is stopped by K, the water flow switch (9) is turned ON in a short time after being turned OFF, and the voltage of the capacitor (0) becomes equal to or higher than the reference voltage in a short time, and ignition occurs immediately.・Combustion operation is performed.

In addition, (16'), (17'), (Tr
) t'i, H shown in the example, (1?), (T
(15') This is a switch circuit that switches to a low voltage state based on Iri ignition.

[Brief explanation of the drawing]

1 to 8 show an embodiment, in which FIG. 1 is a schematic diagram of the water heater, FIG. 2 is a control circuit diagram, and FIG. 8 is a time chart. FIG. 4 is a control circuit diagram showing a conventional example. (9)...Power switch, (C)...Capacitor, (2)...Burner, (River...)
・Combustion operation U1 circuit, (12)...Comparator, (13)...First discharge circuit, (14)...
...Second discharge circuit. 143-

Claims (1)

[Claims] Turn on the power switch (9) and this power switch (9)
When the voltage of the capacitor (0) and this capacitor 10) becomes higher than the reference voltage, a comparator ( 1'4 and burner (2)
is ignited, the first discharge circuit 0, which discharges the voltage of the capacitor tol to a value slightly lower than the reference voltage, and the power switch (9) are turned on.
After a certain period of time has elapsed, when the power switch (9) is on and the burner (2) is in the extinguished state, the voltage of the capacitor 101 is discharged to zero or almost zero. A second discharge circuit 0< is provided, and the capacitor (01 is connected to the second
When the battery is discharged through the discharge circuit (I4) and a certain period of time has elapsed since the power switch (9) was turned on,
Or, when the burner (2) is extinguished, the capacitor (
C) All combustion devices configured to initiate charging.